Ashwagandha: five things to know about the evidence
Ashwagandha, or Withania somnifera, is an Ayurvedic herb often marketed as an “adaptogen” for stress, sleep, energy, hormones and much more.
The original version of this article described five established health benefits. Current evidence is more limited, so we have updated it to separate promising research from claims that are not yet well supported.
1. Stress and sleep have the clearest evidence
The US National Center for Complementary and Integrative Health says some ashwagandha preparations may help with stress and insomnia. Studies use different extracts and doses, so results from one product cannot automatically be applied to every supplement.
Evidence for anxiety is still unclear, and ashwagandha should not be treated as a substitute for evidence-based mental-health care.
2. Claims about energy, performance and blood sugar are less certain
You may see ashwagandha promoted for athletic performance, stamina, diabetes or “stabilising blood sugar”. NCCIH says there is not enough evidence to determine whether it is helpful for these conditions.
If you take medicines for diabetes or blood pressure, check with a healthcare professional because ashwagandha may interact with them.
3. It is not a proven treatment for thyroid disease, menopause or infertility
Small studies and laboratory research have generated interest in thyroid hormones, reproductive health and menopause, but the evidence is not strong enough to recommend ashwagandha as a treatment for these conditions.
NCCIH specifically notes insufficient evidence for female infertility and menopause, and advises against use in people with thyroid disorders unless a healthcare professional says otherwise.
4. “Natural” does not mean risk-free
Short-term use, up to around three months, may be safe for many adults, but long-term safety is not well established. Side effects can include drowsiness, stomach upset, diarrhoea and vomiting.
Rare cases of liver injury have also been linked to ashwagandha supplements.
5. Some people should avoid it
- Do not use ashwagandha during pregnancy or while breastfeeding.
- It is not recommended for people with autoimmune or thyroid disorders without medical advice.
- Speak to a clinician before surgery.
- Check for interactions if you take medicines for diabetes, high blood pressure, seizures, thyroid disease, sedation or medicines that suppress the immune system.
Ashwagandha benefits: common questions
What are the main evidence-based benefits of ashwagandha?
The clearest evidence is for some preparations helping with stress and insomnia. Studies use different extracts and doses, so results cannot automatically be applied to every product.
Does ashwagandha help PMS or periods?
Ashwagandha is not an established treatment for PMS, PMDD or period problems. Claims about “balancing female hormones” are stronger than the evidence currently supports.
Can you take ashwagandha when trying to conceive?
There is not enough evidence to recommend it for female infertility, and it should be avoided during pregnancy. If you are trying to conceive, discuss it with a healthcare professional rather than using it as a fertility treatment.
Who should be cautious with ashwagandha?
It can interact with medicines and is not recommended for some people, including those with certain thyroid or autoimmune conditions. Rare cases of liver injury have also been reported.
The bottom line
Ashwagandha has interesting evidence for some stress and sleep outcomes, but that does not make it a proven treatment for every condition attached to the “adaptogen” label. If you use it, choose a reputable product from an appropriate women's supplements range, check whether it is suitable for you and keep the claims in proportion to the evidence.
